383 carb size?

Discussion in 'Troubleshooting & Diagnosis' started by S_ghost, Jun 10, 2021.

  1. S_ghost

    S_ghost New Member

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    Some time ago I installed a blueprint 430hp 383 longblock crate engine in my camaro and have since done nothing but fight with issues of fuel in my oil with it. Now the blueprint website recommends using a 750 carb with it but my mechanic said that was too big and that's why I'm dealing with the fuel in my oil issue. When talking to the blueprint customer service rep he said the same thing, but I'm not sure if that's the case since that's what the website specs on the motor recommend or if they are just trying to screw me on my warranty. Should I have gone with a 600-650? Or should the 750 Holley I put on it have worked?
     
  2. camarochevy1970

    camarochevy1970 Veteran Member

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    a properly tuned 750 should have worked
     
  3. G72Zed

    G72Zed Veteran Member

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    What type of intake do you have, any spacers? A true 180* split dual plane takes a larger carb and is less "size" sensitive, and generally speaking, an open plenum intake setup is carb sensitive.

    A Holley 750 VS is one of the most versatile carbs sizes that you could use, they are not off on their recommendations.

    A Holley with a bad idle circuit, or other internal/tuning issues, regardless of cfm size can play havoc on the idle and transition circuits and run so rich it's washing the cylinders and adding to the dip stick level.
     
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  4. COPO

    COPO Veteran Member Lifetime Gold Member

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    Either carb should work and should not be dumping fuel unless its not properly setup. I’d be cleaning the needle/seat
    and checking the float level. I’ve run both 750 and 780 on my 70 LT1 and both work well. But I would run what the manufacturer tells you, they built it.
     
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  5. Coadster32

    Coadster32 Veteran Member Lifetime Gold Member

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    I have a 600cfm carb on my street driven 383 motor. All carbs in that general size range should work well. They will all need a bit of tuning to get it done though. If you already have a 750 carb, then work with that. You can increase/decrease the sizing as needed. My 600 carb needed to be sized up to accommodate, as expected.
     
  6. rocket dawg

    rocket dawg Veteran Member

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    Ran the 750 on a SBC400 ( 406) It ran strong. Eventually I put on a Sniper EFI unit and cant say enough good things about it so far.
     
  7. 67johnny

    67johnny Veteran Member

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    They ran 780 holleys vacuum secondarys on the 69 302 cubic inch motors with good success.
    Should be no problem on the 383.
    Find a good tuner !
     
  8. G72Zed

    G72Zed Veteran Member

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    X2 ^^^ 67johnny nailed it right there, "Find a good tuner" that's proving to be more and more difficult as the years go by, hence the popularity of EFI swaps, not for power, but a lot easier to get someone to use a laptop then an "old guy" that knows his way around a Holley carb.
     
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  9. COPO

    COPO Veteran Member Lifetime Gold Member

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    My head is my laptop on my Holley 4555. Head works well with no cooling fans.
     
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  10. MChamp

    MChamp Veteran Member

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    what's your fuel pressure?
     

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